SKU: 79711077414

Mishimoto 2017+ GMC 6.6L Duramax L5P Transmission Thermal Bypass Valve Kit

Sale price$133.19 Regular price$147.99
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  • USA
  • CAN

Ships within 48 hours · Estimated delivery Aug 11 - Aug 16

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Description

Mishimoto 2017+ GMC 6.6L Duramax L5P Transmission Thermal Bypass Valve KitThe Allison transmission is the backbone of your L5P Duramax. It's responsible for transmitting large quantities of torque from your V8 diesel powerplant. This torque generates a lot of heat, and if that heat isn't dissipated, it can destroy your transmission. The transmission cooler does a good job of keeping trans fluid temperatures in check, but only if the fluid can reach it. The stock cooling system of the Allison 1000 transmission utilizes an in

The Allison transmission is the backbone of your L5P Duramax. It's responsible for transmitting large quantities of torque from your V8 diesel powerplant. This torque generates a lot of heat, and if that heat isn't dissipated, it can destroy your transmission. The transmission cooler does a good job of keeping trans fluid temperatures in check, but only if the fluid can reach it. The stock cooling system of the Allison 1000 transmission utilizes an in-line thermal bypass valve that controls fluid flow to the transmission cooler. The purpose of this valve is to prevent transmission fluid from flowing to the cooler until it reaches operating temperature. The thermostat inside this valve is prone to failure, however, and when that happens, the fluid never flows to the cooler, and the transmission can overheat. That's why Mishimoto has developed a thermal bypass valve upgrade for your 2017-2019 Chevrolet/GMC 6.6L Duramax. Our CNC-machined aluminum thermal bypass valve not only looks better than the stock unit, but it performs better too. This Mishimoto thermal bypass valve kit includes a fully serviceable thermostat for fast warm-up in cold climates. This kit also includes a thermostat bypass that can be installed to provide constant cooling in warm climates or for use in extreme driving/towing conditions. The Mishimoto thermal bypass valve features strategically machined internal passages, providing improved flow over the stock valve for more effective cooling. In addition, cooling fins machined into the valve body adds even more heat dissipation. This 2017-2019 Chevrolet/GMC 6.6L Duramax L5P Thermal Bypass Valve Kit is built to last a lifetime with a durable black anodized finish and our Mishimoto Lifetime Warranty.
Shipping Notes
  • Free Standard Shipping on $100+ Orders to the USA.
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  • Delivery to the USA:
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Exchange/Return Notes
  • We offer a 30-day return/exchange service after receiving.
  • Final sale items are not eligible for returns or exchanges.
  • To process your return/exchange, please contact us at [email protected]
  • Please click here for more details>>> Return & Exchange Policy
SKU: 79711077414

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Cuba, US
★★★★★ 4
Shiny Small Sequin Blazer
Size: Small, Color: Black
This tuxedo blazer is one for the looks. It’s shiny black 100% polyester material, with a mesh net on the left side that has dark gold plastic sequins sewn on in a tree pattern. The material is taut with seams at the sides and the middle of the back. There is a single button. There are no pockets outside nor inside the jacket. The quality will hold up and is a decent value for the money. This was for a 5’5 male of slim build and fit quite snug. The measurement in inches: 17 - shoulders; 23 - sleeves; 27-1/2 nape to bottom of blazer.
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Reviewed in the United States on April 29, 2026
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George F.
Boise, US
★★★★★ 5
Size a tad small
Size: Large, Color: Black
So many compliments so don’t buy this if you don’t like people to notice. I’d say fits a tad on the small side.
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Reviewed in the United States on December 26, 2025
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Carla
Louisville, US
★★★★★ 5
Very stylish
Size: X-Large, Color: Black
Really nice… my husband received a lot of compliments on our cruise!
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Reviewed in the United States on January 4, 2026
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Ronald Boast
Waukegan, US
★★★★★ 3
Nice blazer
Size: X-Large, Color: Black, Size: X-Large, Color: Black
Product was as described, son wanted it for a dance. Had it taken in a little for more custom fit
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Reviewed in the United States on July 18, 2025
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VGood
Dallas, US
★★★★★ 5
Really stylish
Size: Medium, Color: Black
Looks great. My son wore to a concert for Valentines day. His gf wore a copper dress...looked so good together.
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Reviewed in the United States on April 23, 2026

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